Large efforts are being made in connection with vehicle manufacturing, in particular passenger car manufacturing, to reduce fuel consumption in order to relieve the environment by means of reduced emissions. A reduction in fuel consumption is presently being primarily sought by reducing the weight of vehicles.
Parallel with this, on the other hand, all manufacturers of vehicles intensely strive to design their vehicles safer, in order to reduce the accident risk for the occupants, and this often results in a weight increase because of additional components, for example the installation of transverse rails in the doors and struts in the vehicle cage. The additional weight these entail cannot even remotely be compensated by savings in the interior fittings.
Because of the employment of smaller engines with improved efficiency it becomes increasingly necessary to install auxiliary heaters, especially in vehicles of smaller size and medium size, because smaller engines and improved engine efficiency no longer provide enough waste heat for heating the vehicles sufficiently in winter.
In a further, parallel occurring development, vehicles are being equipped more and more luxuriously in order to gain advantages in the goodwill of the buyer. The standard equipment of vehicles with air conditioners even in the smaller and medium sizes increases at a steep rate.
Because of the increased employment of auxiliary heaters and air conditioners, the gains regarding the reduction in fuel consumption and emissions, which have often been achieved by painful attention to structural details, have all of a sudden been lost.
On the average, air conditioners weigh 15 to 16 kg, i.e., by far more than can ever be saved in components of the interior fittings. Added to this is that air conditioners cause an average fuel increase of 0.6 l per 100 km. If an air conditioner is installed, both the weight savings at other locations as well as the reduced consumption achieved by this are completely or mostly lost. Driving comfort is increased, but consumption and environmental stress are increased.
Auxiliary fuel heaters weigh 2 to 4 kg on the average and consume 0.2 to 0.4 l of fuel per hour. Passive auxiliary heaters, which recover heat from the waste air of the passenger compartment by means of a heat pump, desorption heaters, and the like are limited in their output, most are heavier than auxiliary fuel heaters and because of the use of electric energy are neither more efficient and in particular not more ecological.
Surprisingly and in a way hard to understand, parallel developments therefore take place in the manufacture of passenger cars each of which, when examined by itself, can be considered to be an improvement, but which as a whole mutually cancel each other partially out in regard to their ecological consequences. The total balance is rather disappointing.
From the viewpoint of ecology, the strong trend toward air conditioners in particular is a serious backward step. It leads to a considerable increase in fuel consumption and therefore to increased emissions of noxious matter. This becomes clear, inter alia, from the recent demands, even from the automobile club sector, to require the manufacturers of vehicles to openly disclose among the technical vehicle data the increase of fuel as a result of the use of air conditioners, so that the buyer can clearly see what additional operating costs he will have to reckon with in connection with air conditioners, and most of all how he has to pay for the luxury of an air conditioner with additional stresses on the environment.
A vehicle in accordance with the species is known from U.S. Pat. No. 2,768,672, which has a partial thermal insulation, which consists of the attachment, or respectively the connection, of asbestos mats with xe2x80x9csurfaces of the interior bordering the exteriorxe2x80x9d and which is limited to this. The intended thermal insulation in this known solution must be paid for with disadvantages (for example higher weight because of the asbestos mats), which neutralize at least a portion of the advantages of thermal insulation.
The invention has as its object the achievement of reduced energy consumption of, and therefore reduced emissions of noxious material by, motor vehicles. This is to be achieved in particular when additional measures for heating and/or air conditioning cannot or should not be omitted which, for the above stated reasons, result in a considerable worsening of the total ecological balance of the system called xe2x80x9cvehiclexe2x80x9d.
For achieving this goal, it is intended in accordance with the invention to intensively thermally insulate vehicles, in particular those parts in which the passengers are, and expanded areas of the vehicle in which thermal insulation is possible in accordance with their structure and function, for example trunks, cargo compartments, and the like. Thermal insulation in the sense of the present application is to be understood to mean that portions of the vehicle which border it on the outside, such as doors, tops, floor components, door sills, pillars, transverse and longitudinal supports, trunk enclosures and the like are to be provided with thermally insulating layers or thermally insulating molded parts as insulating bodies to the extent that this is constructively possible.
Further than that, in accordance with the invention it is intended to design the thermal insulation component-specifically and to employ it in this way, so that its use as xe2x80x9conly thermal insulationxe2x80x9d can be far exceeded in that the remaining properties of the respective components are also improved, as will be represented in detail in what follows:
Initially it is prevented that in summer heat can flow, scarcely stopped, into the interior, in particular into the passenger compartment which would, if air conditioning were to be installed, require a correspondingly large cooling capacity. The expense of thermal insulation is very much less than that for an air conditioner, and so is the weight. In contrast to an air conditioner, it does not cause any operating costs and especially no emissions.
As a rule, an effective thermal insulation will obviate the installation of air conditioners in vehicles in the lower and medium price range, or at least a much smaller installation will be sufficient. With vehicles where it is not possible to omit an air conditioner in spite of thermal installation, an air conditioner with a fraction of the cooling capacity will be sufficient. Naturally, smaller air conditioner use up less energy and cause proportionally reduced emissions. Also, weight is saved with them, which results in further energy savings.
Thermal insulation which reduces the penetration of heat in the summer also prevents the loss of heat in the winter. Vehicles can be kept warm in winter with a reduced use of energy. The amounts of waste heat, which become increasingly less, are then sufficient to heat the vehicles. The auxiliary heaters can be omitted to a large extent, or at least those with less heat output will be sufficient. In this case, too, weight as well as fuel is saved. Fuel is saved even in a twofold manner, namely for the generation of heated air itself, as well as for driving the increased weight or the auxiliary heater.
Thermal insulation can be provided to a large extent by the use of renewable raw materials. Therefore these should be preferably used. Renewable materials do not cause emissions, but the opposite instead. In the course of their assimilation, CO2 already present in the air is reduced and oxygen is released. All possibilities of insulating material, or respectively insulating body designs, can be used by the combination with binding agents and foams made from synthetic plastic materials, derivations of natural materials and/or biogenous materials.
Effective thermal insulation also automatically results in an important addition to improved traffic safety: as determined by a study by Txc3x9cV [Technical Inspection Service], a temperature increase in the vehicle from 25xc2x0 C. to 35xc2x0 C. reduces the fitness of a driver in traffic to the same degree as a blood alcohol content of 0.5 per thousand.
Combined with reinforcement and/or planking elements, for example by means of sheet metal, thermal insulating materials in the form of insulation bodies can also result in considerable mechanical protection and can completely or partially replace the metal rails, which of late have been installed in vehicle doors for improving side impact protection.
The omission of the rails also saves weight. Thus, the replacement of the rails by rigid and energy-dissipating thermal insulation elements, together with the outside and inside sheet metal panels of doors, can take place without significant weight increase, a weight reduction might possibly be conceivable; a complete foam filling of, for example, vehicle doors for the purpose of thermal insulation already demonstrably increases the moment of resistance of the door considerably in comparison with a hollow door as is being constructed in accordance with the prior art. In the course of tests, the reinforcement of the thermal insulating foams by fibers, yarns, stalks, non-wovens, fabrics and similar structures, preferably made of renewable raw materials, has resulted in a further considerable increase in strength. Even when reducing the sheet metal thickness by half, it was possible to achieve strength values which lay far above those in accordance with the prior art, and this even with a reduced total weight.
A thermal insulation in the way shown above with additional reinforcement steps also achieves safety functions in a dual manner: even without air conditioners, or with low cooling capacities, it is possible to maintain the interior climate of vehicles in ranges, which are helpful to the driving fitness of the driver. In the case of a crash, the vehicles provided with thermal insulation in the described manner offer great sturdiness and a large ability for absorbing impact energy. Said thermal damping elements also do not splinter into sharp edges.
Further advantages of the said thermal insulating elements reside in acoustic insulation. A low noise level in the vehicle, besides a pleasant temperature, is a further prerequisite for a very good driving fitness of the driver. He does not get tired as quickly and is less stressed by nerves. Already, some vehicle manufacturers reduce the interior noise generation in particularly critical zones by means of felt. Separate acoustic insulation measures are superfluous in an intensely thermally insulated vehicle, since thermal insulation designed in this manner also increases acoustic insulation as an intentional or unintentional side effect.
Thermal insulation measures taken in accordance with the invention permit the reduction of the thickness of the body sheet metal without loss in strength, especially if the thermal insulation elements are fixedly connected with the body sheet metal, for example by foaming or adhesion. Insulating elements, in particular those reinforced in the described manner, can partially assume supporting functions in the place of sheet metalxe2x80x94a considerable contribution to easier recycling and better ecology.
Besides the above mentioned tendencies, which are counterproductive from an ecological point of view, the developments in vehicle construction also show a tendency toward xe2x80x9cvehicle modulesxe2x80x9d. For example, in the future a door should no longer be delivered in many individual parts by different suppliers to the passenger car manufacturer and only be assembled there, but should be delivered completely as a xe2x80x9cmodulexe2x80x9d, so that it only need to be hung. Thermal insulation elements produced in the described manner can, if they are reinforced in accordance with the invention, take on the functions of a support of functional elements, for example window lifts, door locks, etc., in addition to thermal insulation and accident protection, and with a decorative interior can replace the interior paneling of the old style as decorative single purpose elements, so that to this extent the solution in accordance with the invention also takes this development into account.